Heads up: intact skull sheds light on big, long-necked dinosaurs

WASHINGTON (Reuters) - A beautifully preserved fossil skull unearthed in Argentina is giving scientists unparalleled insight into the sensory capabilities and behavior of a group of dinosaurs that were the largest land animals in Earth's history.

Scientists announced on Tuesday the discovery of the skull as well as neck bones of a newly identified dinosaur called Sarmientosaurus that roamed Patagonia 95 million years ago. CT scans of the skull revealed its brain structure and provided close understanding of its hearing, sight and feeding behavior.

Sarmientosaurus, about 40-50 feet long (12-15 meters) and 8-12 tons, belonged to a group called titanosaurs, plant-eating dinosaurs known for long necks, long tails and huge bodies.

Sarmientosaurus was a medium-sized titanosaur. The largest species exceeded 100 feet (30 meters) and 50 tons. Of the 60 known titanosaur species, only four, including Sarmientosaurus, have been found with complete skulls.

"The head is key to understanding an animal's biology. It's home to the brain, sense organs, jaws and teeth - food-gathering mechanisms - and more," said paleontologist Matt Lamanna of the Carnegie Museum of Natural History in Pittsburgh.

Titanosaurs were part of a larger group of similar dinosaurs called sauropods.

"As for its brain, Sarmientosaurus, bless its heart, was not the sharpest tooth in the jaw," Ohio University anatomist Lawrence Witmer said.

"Sauropod dinosaurs in general are famous for having the smallest brain size relative to body size, and Sarmientosaurus was no exception. Its brain was about the size of a lime yet its body weighed as much as two or three elephants."
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